1. Field of the Invention
This invention relates to a fiber optic terminus, and more particularly, to a novel construction and method for securely holding an optical fiber in the fiber optic terminus.
2. Description of Related Art
It is conventional practice to couple optical fibers utilizing a fiber optic pin terminus and a fiber optic socket terminus. Separate optical fibers are carried by the pin terminus and the socket terminus. A portion of the pin terminus is receivable in the socket terminus to optically couple the optical fibers.
It is important that optical fibers be coupled in a manner to minimize optical losses at the interface between fibers. This requires that the fibers be accurately axially aligned, and this is particularly difficult because optical fibers are typically of very small diameter. In any event, it is important to accurately and tightly secure the fibers to the associated terminus to assist in minimizing optical losses.
It is known to use an adhesive to attach optical fibers to a terminus. However, the adhesives commonly used for this purpose usually require curing time and have a limited shelf life. Adhesives tend to be messy and are not well suited for use in the field.
Another technique of affixing an optical fiber to a terminus is to radially crimp the metal of the terminus at the attachment site such that the optical fiber is radially clamped. This can produce regions of concentrated or high pressure on the optical fiber even if a relatively ductile material, such as lead, is interposed between the optical fiber and the body of the terminus. The regions of relatively high pressure can produce microbends in the fiber, and this condition produces optical losses. In addition, if the terminus is subjected to widely fluctuating temperatures, the radial crimping forces acting on the fiber will increase and then decrease during temperature swings. This may cause the fiber to loosen, or at the other extreme, to be subjected to excessive pressure and the related risks of microbending.
Common assignee's copending application Ser. No. 091,932 filed on Sept. 1, 1987 discloses a fiber optic terminus which employs a temperature-activated adhesive to adhere an optical fiber in the passage of a fiber optic terminus. The adhesive is flowable when its temperature is raised to a predetermined level. Consequently, the design does not lend itself to high-temperature applications where the ambient temperature consistently exceeds that at which the adhesive is activated, i.e., becomes flowable.